Rockwell 1756 modules face DoS flaw
A CIP packet validation flaw in Rockwell Automation 1756-EN2, EN3, and ENBT communication modules can be exploited to disrupt device connections.
Sourcecisa.gov — open the original
What to check
- Applies to
- The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
CISA has published an advisory for a denial-of-service vulnerability affecting Rockwell Automation's 1756-EN2, 1756-EN3, and 1756-ENBT communication modules, used across critical manufacturing environments worldwide. The flaw, tracked as CVE-2026-9653, stems from improper validation of CIP Implicit Connection packets, allowing an attacker with network access to send crafted packets that continuously disrupt device connections. Connections recover automatically once the malicious traffic stops, limiting the impact to transient disruption rather than persistent outage.
Rockwell has released fixes for 1756-EN3 and 1756-EN2 (update to V12.002), while the 1756-ENBT module is discontinued and will not receive a patch. CISA notes no known public exploitation of this vulnerability at this time and recommends standard ICS network segmentation practices — isolating control system networks from business networks and the internet, and using VPNs for remote access. The vulnerability was responsibly reported by a researcher at Idaho National Laboratory.
Mentioned in this report
Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-26-197-02
Free public brief. Slack alerts on the vendors you run come with the paid plans, and a new account gets three days of them, no card.
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries live profiles of the CVEs it names. The paid plans add the security research and news reporting the free tier leaves out.
It sits in a corpus of 16,436 reports from 149 sources, 661 of them written in the last seven days, and it grows through the day.
A new account starts with three days of all of it, no card, then keeps the government and CERT reporting free. Slack alerts are a paid-plan feature: name the vendors you run and Slack hears about the reports that touch them, not the rest of the week's. Nothing is charged unless you subscribe.
Create a free account What it costs